Telcordia Technologies, Inc. v. Cisco Systems, Inc.

United States Court of Appeals
for the Federal Circuit
__________________________

TELCORDIA TECHNOLOGIES, INC.,
Plaintiff-Appellant,
v.
CISCO SYSTEMS, INC.,
Defendant-Cross Appellant.
__________________________

2009-1175, -1184
__________________________

Appeals from the United States District Court for the
District of Delaware in case no. 04-CV-876, Chief
Judge Gregory M. Sleet.
___________________________

Decided: July 6, 2010
___________________________

DONALD R. DUNNER, Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P., of Washington, DC, argued for
plaintiff-appellant. With him on the brief were DON O.
BURLEY, DARREL C. KARL, and JOHN M. WILLIAMSON.

EDWARD R. REINES, Weil, Gotshal & Manges LLP, of
Redwood Shores, California, argued for defendant-cross
appellant. With him on the brief was SONAL N. MEHTA.
__________________________
TELCORDIA TECH v. CISCO SYSTEMS 2

Before RADER * , Chief Judge, LOURIE and PROST, Circuit
Judges.
Opinion for the court filed by Chief Judge RADER. Opin-
ion dissenting in part filed by Circuit Judge PROST.
RADER, Chief Judge.
Telcordia Technologies, Inc. (“Telcordia”) initiated this
suit against Cisco Systems, Inc. (“Cisco”) alleging in-
fringement of U.S. Patent Nos. 4,893,306 (“’306 patent”);
4,835,763 (“’763 patent”); and RE 36,633 (“’633 patent”).
The United States District Court for the District of Dela-
ware granted summary judgment of non-infringement of
the ’306 patent. Telcordia Techs., Inc. v. Cisco Sys., Inc.,
514 F. Supp. 2d 598, 603-07 (D. Del. 2007). At trial, the
jury found that Cisco willfully infringed the ’763 and ’633
patents and upheld the validity of all three asserted
patents. The jury awarded $6.5 million in damages.
Following trial, the district court denied Cisco’s motion for
judgment as a matter of law (“JMOL”) that the ’306
patent was anticipated and that the ’763 patent was
invalid as indefinite. Telcordia Techs., Inc. v. Cisco Sys.,
Inc., 592 F. Supp. 2d 727, 738-40, 743-44 (D. Del. 2009).
The district court awarded prejudgment interest on the
$6.5 million damages award. Id. at 748-50. Further, the
district court awarded an accounting for interim sales
from January 31, 2007 to the date of the judgment. Id. at
748-50. In addition, the district court ordered the parties
to negotiate the terms of a royalty that would apply to the
accounting and to post-judgment sales. Id.
On appeal, Telcordia challenges the district court’s
claim construction with respect to the ’306 patent. Cisco
cross-appeals the district court’s holding that the asserted

* Randall R. Rader assumed the position of Chief
Judge on June 1, 2010.
3 TELCORDIA TECH v. CISCO SYSTEMS

claims of the ’306 and ’763 patents are not invalid. Cisco
also contests the district court’s award of an accounting
and pre-judgment interest, and its order requiring the
parties to negotiate the royalty.
Because the district court erroneously construed the
only term on which it based its denial of Cisco’s JMOL
motion on invalidity of the ’306 patent, this court vacates
that decision and remands for determination of the valid-
ity issue. This court also remands to provide the parties
an opportunity to negotiate the terms of the royalty. In
all other respects, this court affirms.
I.
Telcordia owns by assignment the ’306 patent, the
’763 patent, and the ’633 patent. The patents relate to
transmission of data in telecommunications networks.
The ’306 patent—“Method and Apparatus for Multiplex-
ing Circuit and Packet Traffic”—issued on January 9,
1990, based on a November 10, 1987 application. The
’763 patent—“Survivable Ring Network”—issued on May
30, 1989, based on a February 4, 1988 application. The
’633 patent—”Synchronous Residual Time Stamp for
Timing Recovery in a Broadband Network”—issued on
March 28, 2000, as a reissue of U.S. Patent No. 5,260,978.
A.
The ’306 patent describes a data transmission tech-
nique called Dynamic Time Division Multiplexing
(“DTDM”). DTDM is compatible with both the circuit
transmission format and the packet transmission format.
In the late 1980’s, the public telephone network began
shifting from the circuit transmission format to the packet
transmission format. The “commonly-held view as to how
to introduce packet technology into the public network
[was] to deploy a packet overlay network.” ’306 patent
TELCORDIA TECH v. CISCO SYSTEMS 4

col.3 ll.3-18. This migration strategy required building a
packet transmission network on top of a circuit transmis-
sion network. The patented invention aimed to provide
an alternate migration strategy between the two different
transmission formats.
A system implementing DTDM allocates discrete
segments, or “frames,” of a single transmission line to
several sources (e.g., voice, video, and data). A frame is
the basic unit of transmission:

Id. at fig.1. Each frame has two fixed-length fields: a
transmission overhead (“T”) and a payload. The trans-
mission overhead has, for example, frame timing informa-
tion and the empty/full status of the frame. The payload
field has a header field (“H”) for storing the sender’s and
recipient’s addresses, and an information field for storing
the actual data for transmission. Rather than pre-assign
the frames to each information source, the DTDM system
dynamically allocates the frames to each source based on
the source’s priority level and data availability.
Figure 2 illustrates how a multiplexer called a
“DTDM Assembler” (3) merges traffic from three different
information sources (5, 7, 9) into a single DTDM bit
stream (12).
5 TELCORDIA TECH v. CISCO SYSTEMS

Id. at fig.2. The system generates a train of DTDM
frames (10) with occupied transmission overhead fields
and empty payload fields. Id. at col.4 l.65-col.5 l.2. This
train has “a bit rate which defines a basic backbone
transmission rate” for the system. Id. at col.5 ll.2-4. The
information sources transmit, for example, voice (5), video
(7), and data (9), over their data lines or “tributaries.”
The incoming data segments may be in the circuit trans-
mission format or the packet transmission format. Pack-
etizers (11, 13, 15) put the incoming data segment into a
packet structure by adding a packet header (“H”) at the
beginning of each data segment. The DTDM assembler
inserts the packets into the empty payload fields of the
DTDM frames. If the DTDM assembler simultaneously
receives packets from multiple information sources, the
DTDM assembler selects the packet with the highest
priority level. The resulting DTDM bit stream (12) con-
tains packets from multiple information sources.
Telcordia alleges that Cisco infringes claims 1, 3, and
4 of the ’306 patent. Claims 1 and 3 are method claims.
Claim 4 is an apparatus claim. Each is stated below
(important phrases underlined):
TELCORDIA TECH v. CISCO SYSTEMS 6

1. A method for simultaneously transmitting data
from sources having different bit rates in a tele-
communication network comprising the steps of:
generating a bit stream comprising a sequence of
frames, each of said frames including a transmis-
sion overhead field containing frame timing in-
formation and an empty payload field, and
filling the empty payload fields in said frames
with data in packetized format from a plurality of
sources which have access to the bit stream in-
cluding circuit or packet sources, such that data in
packetized format from any of said sources is writ-
ten into any available empty payload field of any
of said frames for transmitting data from each of
said sources at its own desired bit rate via said bit
stream and for transmitting data from said plu-
rality of sources simultaneously via said bit
stream.
Id. at col.17 ll.44-61 (emphases added).
3. A method for generating a bit stream capable of
transporting data originating from both circuit
transmission and packet sources comprising
generating a bit stream comprising a sequence of
frames, each of said frames including a transmis-
sion overhead field containing frame timing in-
formation and an empty payload field,
packetizing data from a plurality of sources hav-
ing different bit rates and which have access to
said bit stream including circuit transmission
sources or customer premises equipment to pro-
duce data packets, and
7 TELCORDIA TECH v. CISCO SYSTEMS

inserting said packets from said sources into the
empty payload fields of said frames such that a
packet from any of said sources is inserted into any
available empty payload field of any of said
frames for transmitting data from each of said
sources at its own desired bit rate via said bit
stream and for transmitting data from said plu-
rality of sources simultaneously using said bit
stream.
Id. at col.18 ll.1-20 (emphases added).
4. An apparatus for assembling a dynamic time
division multiplexing bit stream comprising,
generating means for generating a train of frames
wherein each frame includes a transmission over-
head field containing timing information and an
empty payload field,
processing means for processing data from a plu-
rality of sources into packet format, and
inserting means for receiving said train of frames
and for inserting each of said packets comprised of
data from one of said plurality of sources into any
empty payload field of any of said frames available
to said inserting means to form said bit stream so
that data from each of said sources can be trans-
mitted at its own desired bit rate via said bit
stream and so that data from said plurality of
sources can be transmitted simultaneously via
said bit stream.
Id. at col.18 ll.21-37 (emphases added).
TELCORDIA TECH v. CISCO SYSTEMS 8

B.
The ’763 patent claims a survivable or self-healing
ring network that can withstand a cut line or failed node.
Figure 2 illustrates the invention:

’763 patent fig.2.
The invention consists of two rings carrying identical
multiplexed node-to-node communications in opposite
directions. A node (1), for example, has controllers (117,
118) and selectors (119-121). Each node can detect a
break (122) in either ring by monitoring the arriving
signals for defects. If an arriving signal is defective, the
controller in the node inserts an error signal on the spe-
cific channels that were lost due to the break. When
9 TELCORDIA TECH v. CISCO SYSTEMS

these error-containing channels reach their destination
node, the selector in the node will detect the error signal
and select the identical, error-free channels from the
other ring.
Monitoring of errors in the arriving signals is essen-
tial to the invention. The asserted independent claims 1
and 7 both claim this functionality via the “monitoring
means” requirement. Claim 1 is illustrative (important
phrase underlined):
1. In a communications network having a plural-
ity of nodes interconnected in a ring configuration
by a first ring which conveys multiplexed subrate
communications around the first ring from node to
node in one direction and a second ring which
conveys multiplexed subrate communications
around the second ring from node to node in the
other direction, each node including subrate
transmitters with associated multiplexers and
demultiplexers with associated subrate receivers,
an improved node comprising
monitoring means, associated with the first ring
and the second ring, for evaluating the integrity of
the multiplexed subrate communications on the
first ring and the second ring, respectively, and
insertion means, associated with the demultiplex-
ers and said monitoring means, for inserting an
error signal on designated ones of the subrate
communications in response to said monitoring
means detecting a lack of integrity on the multi-
plexed subrate communications on the first ring
or the second ring or both the first ring and the
second ring.
Id. at col.4 l.53-col.5 l.5 (emphasis added).
TELCORDIA TECH v. CISCO SYSTEMS 10

C.
The accused products are Cisco routers and switches
that transmit asynchronous transfer mode (“ATM”) cells
and other types of packets over synchronous optical
network (“SONET”). SONET is an industry standard for
optical transmission. ATM is a protocol for dividing data
from multiple sources into small segments called “cells”
and intermixing those cells for transmission across a
network. The accused routers and switches purportedly
have SONET framers that multiplex the ATM cells into a
frame called a Synchronous Transport Signal One.
D.
Telcordia sued Cisco for infringement of the ’306, ’633,
and ’763 patents. On June 22, 2006, the district court
issued a claim construction order. Telcordia conceded
that it could not establish infringement of the ’306 patent
based on the district court’s claim construction. Specifi-
cally, Telcordia could not prove that the accused Cisco
products met the following limitations: (1) the “empty
payload fields” limitations of claims 1, 3, and 4; and (2)
the “having access” limitations of claims 1 and 3. The
district court, however, denied Telcordia’s Rule 54(b)
motion to have a judgment of non-infringement of the ’306
patent entered against it.
Cisco then moved for a summary judgment of non-
infringement of the ’306 patent. Cisco argued that the
accused products lacked not only the two claim limita-
tions that Telcordia had conceded were missing but four
additional claim limitations. The district court granted
Cisco’s motion “on all grounds raised by [Cisco].” Telcor-
dia, 514 F. Supp. 2d at 603-07.
In April to May 2007, the district court held a trial on
infringement of the ’633 and ’763 patents and validity of
11 TELCORDIA TECH v. CISCO SYSTEMS

all three patents. On May 10, 2007, the jury returned a
unanimous verdict for Telcordia on all claims. The jury
found that Cisco willfully infringed all asserted claims of
the ’633 and ’763 patents. The jury also upheld the valid-
ity of the ’306, ’633, and ’763 patents. On May 16, 2007,
the district court entered a judgment on the verdict.
On January 6, 2009, the district court granted Telcor-
dia’s motion for an award of prejudgment interest and an
accounting of Cisco’s infringing sales from January 31,
2007 to the date of the judgment. Telcordia, 592 F. Supp.
2d at 748-50. The district court ordered the parties to
negotiate the terms of the royalty. Id. The district court
denied Cisco’s JMOL motion that the asserted claims of
the ’306 patent claims are invalid as anticipated. Id. at
743-44. The district court also denied Cisco’s JMOL
motion that the asserted claims of the ’763 patent are
invalid as indefinite. Id. at 738-40.
On appeal, Telcordia challenges the district court’s
claim construction and summary judgment of non-
infringement of the ’306 patent. Cisco cross-appeals the
district court’s denial of its JMOL motions on validity of
the ’306 and ’763 patents. Cisco also appeals the district
court’s damages awards. This court has jurisdiction
under 28 U.S.C. § 1295(a)(1).
III.
Telcordia challenges the district court’s construction
of six terms in the ’306 patent, all of which formed inde-
pendent grounds for the district court’s summary judg-
ment of non-infringement. This court first construes the
term “empty payload field” in claims 1, 3, and 4, as the
definition affects other construed terms. Because this
court agrees with the district court’s construction of the
term “such that . . . [a packet is inserted into] any avail-
able empty payload field” in claims 1 and 3, and the term
TELCORDIA TECH v. CISCO SYSTEMS 12

“inserting means” in claim 4, this court affirms the judg-
ment of non-infringement of the ’306 patent.
A.
Claim construction is an issue of law that this court
reviews without deference. Cybor Corp. v. FAS Techs.,
Inc., 138 F.3d 1448, 1455-56 (Fed. Cir. 1998) (en banc).
The claim terms “are generally given their ordinary and
customary meaning.” Phillips v. AWH Corp., 415 F.3d
1303, 1312 (Fed. Cir. 2005) (en banc) (quotation omitted).
“[T]he claims themselves provide substantial guidance as
to the meaning of particular claim terms.” Id. at 1314.
Also, a patent’s specification “is always highly relevant to
the claim construction analysis.” Id. at 1315 (quotation
omitted). Courts should also consider prosecution history
of the asserted patents. Id. at 1317. However, because
prosecution history represents an ongoing negotiation
between the United States Patent and Trademark Office
and the inventor, “it often lacks the clarity of the specifi-
cation and thus is less useful for claim construction
purposes.” Id.
B.
As noted, claims 1, 3, and 4 of the ’306 patent claim “a
transmission overhead field containing frame timing
information and an empty payload field.” The district
court construed the term “empty payload field” to mean “a
payload field that is empty of source data, but including
bit signals of some kind, i.e. garbage bits.” Telcordia
Techs., Inc. v. Cisco Sys., Inc., No. 04-cv-876, slip. op. at 6
(D. Del. June 22, 2006) (“Claim Construction Order”). The
parties dispute whether the claim construction includes
the explanatory phrase “i.e. garbage bits,” which, accord-
ing to the parties, limits the “bit signals of some kind” to
“bits that serve no purpose other than place-holding.”
13 TELCORDIA TECH v. CISCO SYSTEMS

The empty payload fields are “empty” of data packets
and therefore have non-source bit signals only. The
specification explains that “a train of DTDM frames with
empty payload fields . . . has a bit rate which defines a
basic backbone transmission rate for the DTDM system.”
’306 patent col.7 ll.27-30. Therefore, the bit signals help
the DTDM system maintain a bit stream even when it is
not transmitting data from an information source. The
specification does not specify where in the frame the “bit
rate” is stored nor does it specify the type of non-source
bits used to maintain the bit rate. Therefore, nothing in
the ’306 patent restricts the bit signals in the empty
payload field to ones that serve no purpose other than
place-holding.
The district court apparently took the explanatory
phrase from an ad lib comment made during an oral
hearing at the Federal Circuit. In Bell Communications
Research, Inc. v. FORE Systems, Inc., Nos. 02-1083, 02-
1084, 2003 WL 1720080 (Fed. Cir. Mar. 27, 2003), Bell
Communications Research, Inc., now known as Telcordia,
asserted the ’306 patent against another defendant. This
court reviewed a district court’s construction of the term
“empty payload field” in the ’306 patent. Id. In that case,
the district court had explained that “a frame’s payload
has zero data in it.” Id. at *6. During oral hearing, Bell
Communications agreed with Circuit Judge Bryson’s
characterization of bits in the “empty payload fields” as
“garbage:”
Judge Clevenger: Can we come back to the empty
payload field? “Empty” seems to me . . . the com-
mon meaning of the word “empty” means there is
nothing there. So, you are saying that there is
something in the written description that tells me
what empty means?
TELCORDIA TECH v. CISCO SYSTEMS 14

Bell Communications’s Counsel: I am saying . . . .
Judge Clevenger: Where in the written descrip-
tion?
Bell Communications’ Counsel: A144, column 7,
lines 29-35. And, what you will see there at that
point . . . .
Judge Clevenger: There is a bit rate.
Bell Communications’s Counsel: It says, “this
train.” It is talking about empty payload field.
“This train 10 has a bit rate.” In other words, it’s
empty, but it has a bit rate. Because in order to
have . . . sometimes there won’t be a packet ready.
The stream must continue. There must be a bit in
the stream. It just won’t be a data bit, it won’t be
a source data bit. It will be a bit. And it will have
information in it, but it won’t be source informa-
tion.
Judge Bryson: It would just be garbage, I take it.
I mean it will just be 1’s and 0’s that have no rela-
tionship to the stream of any information that’s
coming in from the source.
Bell Communications’s Counsel: Exactly, Your
Honor.
The issue on appeal, at least initially, seemed to be
whether the district court actually meant “no bit signals
of any kind” when it said “zero data.” Id. At oral hearing,
however, Fore Systems, Inc. stated its understanding that
“‘zero data’ encompasse[d] various bit signals that might
maintain the stated transmission rate of a bit stream,
including ‘placeholders’ or ‘garbage bits.’” Bell Commc’ns,
2003 WL 1720080, at *6. Because the parties’ agreement
on this broader interpretation of “zero data” rendered the
15 TELCORDIA TECH v. CISCO SYSTEMS

claim construction issue moot, this court declined to refine
the district court’s construction. Id.
The claim construction issue on appeal in the present
case—whether the empty payload field only has bits that
act as placeholders—is different from the one in Bell
Communications—whether the empty payload field has
any bits at all. Circuit Judge Bryson’s comments, there-
fore, are not directly relevant to the specific issue in the
present case. The district court erred by limiting the claim
scope based on the ad lib comment from the bench.
In addition, contrary to Cisco’s assertion, Telcordia
has not changed its proposed claim construction of “empty
payload field.” In Bell Communications, Telcordia agreed
that the empty payload fields only have “garbage bits”
because it understood the phrase “garbage bits” to mean
bits with “no relationship to the stream of any informa-
tion that’s coming in from the source.” In the present
case, Telcordia disputes the claim construction with the
phrase “garbage bits” because the district court appar-
ently meant “non-source bit signals that serve no purpose
other than place-holding.” Thus, Telcordia is not pre-
cluded from making the claim construction arguments
that it makes now.
Accordingly, “empty payload field” means “a payload
field that is empty of source data, but includes bit signals
of some kind.”
C.
As noted, claim 1 of the ’306 patent claims “such that
data in packetized format from any of said sources is
written into any available empty payload field of any of
said frames.” Claim 3 recites “such that a packet from
any of said sources is inserted into any available empty
payload field of any of said frames.” Claim 4 recites
TELCORDIA TECH v. CISCO SYSTEMS 16

“inserting each of said packets comprised of data from one
of said plurality of sources into any empty payload field of
any of said frames available to said inserting means.”
The district court construed all three claim elements to
require that the “packets are only put into frames which
are empty.” Claim Construction Order at 6-7. The dis-
trict court further clarified that the claims encompass
only one packet per frame. Telcordia Techs., Inc. v. Cisco
Sys., Inc., 514 F. Supp. 2d 598, 606 (D. Del. 2007). Each
SONET frame in the accused products carries multiple
ATM cells or packets. Id. Telcordia therefore concedes on
appeal that it cannot prove infringement if the asserted
claims encompass only one packet per frame.
This court agrees with the district court’s construction
that each frame in the DTDM bit stream can carry only
one data packet. The specification clearly limits the
disclosed mechanism to one packet per frame.
Figure 2, which “illustrates the formation of a DTDM
bit stream,” ’306 patent col.7 ll.14-15 (emphasis added),
shows a DTDM assembler inserting one packet into each
empty payload field. Also, the DTDM assembler’s struc-
ture only allows it to insert one packet per frame. The
DTDM assembler reads data from a FIFO queue of data
packets if two conditions are met. The first condition is
that at least one full packet is stored in the FIFO queue.
The second condition is that “the incoming DTDM frame .
. . is not already occupied by a valid packet, i.e. the incom-
ing DTDM frame is empty.” Id. at col. 9 ll.38-41. Thus,
an “empty” frame is one that “is not already occupied by a
valid packet.” Id. at col.9 ll.38-41 (emphasis added). If
the presence of one packet makes a payload field not
“empty,” the next packet, which must be inserted into an
empty DTDM frame, must wait for the next available
frame. Therefore, the DTDM assembler cannot insert
more than one data packet into a frame.
17 TELCORDIA TECH v. CISCO SYSTEMS

Moreover, the specification further explains that
when the FIFO queue has a packet ready, it “triggers an
enable signal . . . to be asserted for the whole frame
transmission period allowing the data packet to be moved
from the FIFO through the framer and into the DTDM bit
stream.” Id. at col.9 ll.42-47 (emphasis added). Only one
data packet can move from the FIFO queue to the DTDM
bit stream during “the whole frame transmission period,”
indicating that each frame can store only up to one
packet. By repeatedly describing the inventive DTDM
mechanism as one that only allows one packet per frame,
“the patentee has demonstrated a clear intention to limit
the claim scope using words or expressions of manifest
execution or restriction.” Liebel-Flarsheim Co. v. Medrad,
Inc., 358 F.3d 898, 905 (Fed. Cir. 2004) (internal quota-
tion omitted).
This court recognizes that during the prosecution of
the ’306 patent, the applicant made statements suggest-
ing that a frame may be able to store more than one
packet:
[A]n empty payload field of each frame may be
filled with a data packet including a header. […]
In certain cases, it may be possible for a payload
field of a frame to have the capacity for more than
one packet.
Although this statement suggests that “it may be possible
for a payload field” to contain multiple data packets, the
specification does not disclose any mechanisms that would
allow more than one packet per frame. These prosecution
history comments cannot trump the plain language of the
claims and the direct teaching of the specification. See
Biogen Inc. v. Berlex Labs., Inc., 318 F.3d 1132, 1140 (Fed.
Cir. 2003) (“Representations during prosecution cannot
enlarge the content of the specification . . . .”).
TELCORDIA TECH v. CISCO SYSTEMS 18

Accordingly, the ’306 patent discloses a DTDM
mechanism in which each frame can store only one data
packet. This court agrees with the district court’s claim
constructions of the “such that” limitation in claims 1 and
3, and the “inserting means” limitation in claim 4. Be-
cause Telcordia concedes that it cannot prove infringe-
ment based on these claim constructions, this court
affirms the district court’s grant of summary judgment of
non-infringement.
IV.
“A party seeking a declaratory judgment of invalidity
presents a claim independent of the patentee’s charge of
infringement.” Cardinal Chem. Co. v. Morton Int’l, 508
U.S. 83, 96 (1993). Therefore, this court’s affirmance of
the district court’s non-infringement findings as to the
’306 patent does not moot Cisco’s invalidity counterclaim
on cross-appeal. See Old Town Canoe Co. v. Confluence
Holdings Corp., 448 F.3d 1309, 1318 (Fed. Cir. 2006).
This court reaches Cisco’s argument that the asserted
claims of the ’306 patent are invalid as independently
anticipated by two prior art publications: (1) Description
of FasNet by Limb et al. (“FasNet”); and (2) “A
packet/circuit switch” by Budrikis et al. (“Budrikis”).
The district court denied Cisco’s JMOL motion on in-
validity of the ’306 patent solely on the basis that a rea-
sonable jury could conclude that “the bits used in FasNet
and Budrikis were intentionally placed with some pur-
pose, and thus, were not garbage bits.” Telcordia, 592 F.
Supp. 2d at 744. As noted, this court agrees with Telcor-
dia that the “garbage bits” limitation improperly limits
the scope of the asserted claims. Because the sole basis
on which the district court based its decision is no longer
valid, this court remands to the district court for recon-
19 TELCORDIA TECH v. CISCO SYSTEMS

sideration of Cisco’s invalidity counterclaim under the
revised claim construction.
V.
Title 35 provides that “[t]he specification shall con-
clude with one or more claims particularly pointing out
and distinctly claiming the subject matter which the
applicant regards as his invention.” 35 U.S.C. § 112, ¶ 2.
For a means-plus function claim to satisfy the definite-
ness requirement, the written description must clearly
link or associate structure to the claimed function. Bio-
medino, LLC v. Waters Techs. Corp., 490 F.3d 946, 950
(Fed. Cir. 2007). Whether the written description ade-
quately sets forth the structure corresponding to the
claimed function must be considered from the perspective
of a person skilled in the art. Intel Corp. v. VIA Techs.,
Inc., 319 F.3d 1357, 1365-66 (Fed. Cir. 2003). “The ques-
tion is not whether one of skill in the art would be capable
of implementing a structure to perform the function, but
whether that person would understand the written de-
scription itself to disclose such a structure.” Tech. Licens-
ing Corp. v. Videotek, Inc., 545 F.3d 1316, 1338 (Fed. Cir.
2008). “While corresponding structure need not include all
things necessary to enable the claimed invention to work,
it must include all structure that actually performs the
recited function.” Default Proof Credit Card Sys. v. Home
Depot U.S.A., Inc., 412 F.3d 1291, 1298 (Fed. Cir. 2005).
“A determination of claim indefiniteness is a legal conclu-
sion that is drawn from the court’s performance of its duty
as a construer of patent claims.” Personalized Media
Commc’ns, L.L.C. v. Int’l Trade Comm’n, 161 F.3d 696,
705 (Fed. Cir. 1998).
The district court determined that the term “monitor-
ing means” was a means-plus function term pursuant to
35 U.S.C. § 112, ¶ 6. The district court identified the
TELCORDIA TECH v. CISCO SYSTEMS 20

function of the “monitoring means” to be “evaluating the
integrity of the multiplexed subrate communications on
the first ring and the second ring,” and the corresponding
structure for that function to be “the circuitry at a control-
ler that determines if a defect exists with the multiplexed
subrate communications,” and all equivalents thereof.
Claim Construction Order at 2-3.
The written description of the ’763 patent adequately
discloses the structure for the monitoring means in the
node-to-node communication system. Each node has two
controllers, which are connected to different communica-
tion rings. As each node monitors and evaluates the
integrity of the signals arriving at the node, the control-
lers insert error signals onto the channels when a major
line fault occurs:
Each node continuously monitors and evaluates
the integrity of the multiplexed subrate signals
arriving at the node. Illustratively, this could be
accomplished by detecting the absence of a carrier
signal in an analog signal environment, or the
lack of any incoming signal in a digital environ-
ment. When node 1 recognizes major line fault
122 in ring 100, controller 118 inserts an error
signal onto the six subrate channels. This could
illustratively be accomplished by inserting a
string of 1’s on each channel in a digital environ-
ment. Node 4 performs the identical activity by
similarly placing an error signal on the six
subrate channels of ring 101.
’763 patent col.3 ll.4-17. The nodes have controllers and
selectors; those selectors cannot recognize any errors in
the subrate signals until the signals reach the destined
node. Therefore, the controller must monitor the incom-
ing signals for error; otherwise, the controller would not
21 TELCORDIA TECH v. CISCO SYSTEMS

be able to insert error signals onto the subrate channels.
Dr. Prucnal, Telcordia’s expert, also testified that control-
lers 117 and 118 and their circuitry are the structure
associated with the function of the monitoring means.
Thus, the district court did not err by finding that an
ordinary artisan would understand the written descrip-
tion to clearly link or associate the controller with the
claimed function.
As Cisco notes, the figures of the ’763 patent show the
controller’s circuit as a black box, i.e., nothing in the
figures describes the details of its inner circuitry.
“[H]owever, the absence of internal circuitry in the writ-
ten description does not automatically render the claim
indefinite.” Tech. Licensing, 545 F.3d at 1338. As noted,
claim definiteness depends on the skill level of an ordi-
nary artisan. Intel, 319 F.3d at 1365-66. Therefore, the
specification need only disclose adequate defining struc-
ture to render the bounds of the claim understandable to
an ordinary artisan. Id. (holding that the internal cir-
cuitry of an electronic device need not be disclosed in the
specification if one of ordinary skill in the art would
understand how to build and modify the device). Here,
Dr. Prucnal testified that an ordinary artisan would know
how to interpret the specification and actually build a
circuit. The record shows that an ordinary artisan would
have recognized the controller as an electronic device with
a known structure. Therefore, the specification along
with the figures shows sufficient structure to define the
claim terms for an ordinarily artisan in the relevant field.
Cisco faults Telcordia for not presenting sufficient
evidence that the patent links the controller with the
claimed function of the monitoring means. Cisco, in
particular, challenges Dr. Prucnal’s testimony that the
circuitry in the controller corresponds to the monitoring
means. However, patents are presumed to be valid, and
TELCORDIA TECH v. CISCO SYSTEMS 22

so, Cisco bears the burden of proving that an ordinary
artisan would not understand the disclosure. 35 U.S.C.
§ 282; see Aero Prods. Int'l, Inc. v. Intex Rec. Corp., 466
F.3d 1000, 1015 (Fed. Cir. 2006). The record shows that
Cisco did not show that an ordinary artisan would not
understand the link between the controller and the moni-
toring function. Therefore, this court affirms the district
court’s decision to deny Cisco’s JMOL motion that the
asserted claims of the ’763 patent are indefinite.
VI.
A.
Lastly, this court addresses the district court’s dam-
ages decisions. In reviewing damages awards in patent
cases, this court gives “broad deference to the conclusions
reached by the finder of fact.” Monsanto Co. v. McFarling,
488 F.3d 973, 981 (Fed. Cir. 2007). This court reviews a
district court’s damages decision for “an erroneous conclu-
sion of law, clearly erroneous factual findings, or a clear
error of judgment amounting to an abuse of discretion.”
Mars, Inc. v. Coin Acceptors, Inc., 527 F.3d 1359, 1372
(Fed. Cir. 2008).
B.
Cisco’s challenge to the district court’s damages deci-
sions largely stems from its argument that the jury’s
damages award is a paid-up, lump-sum licensing fee, and
that the district court erred by granting Telcordia addi-
tional relief beyond the jury verdict.
The verdict form asked:
If you have found any claim of Telcordia U.S. Pat-
ent No. 4,835,763 or U.S. Patent No. Re. 36,633 to
be both valid and infringed by Cisco, please iden-
23 TELCORDIA TECH v. CISCO SYSTEMS

tify the amount of monetary damages that will
compensate Telcordia for Cisco’s infringement.
The jury entered “$6,500,000 (6.5 MIL)” on the verdict
form. The verdict form is unclear whether the jury com-
pensated Telcordia only for Cisco’s past infringement or
for both past and ongoing infringement.
During the trial, the parties presented three sets of
damages numbers to the jury. Telcordia’s damages expert
testified that the proper damages award should be based
on a running royalty. Cisco’s expert testified that the
award should be based on a lump-sum, paid-up license.
Cisco’s expert also applied a running royalty analysis to
show the differences between Telcordia’s and Cisco’s
approaches to damages. Id. To complicate the matter
further, the parties also presented different royalty rates
and royalty bases. Therefore, it is unclear whether the
jury based its award on a lump-sum, paid-up license,
running royalty, some variation or combination of the
two, or some other theory.
District courts have broad discretion to interpret an
ambiguous verdict form, because district courts witness
and participate directly in the jury trial process. The
district court was in a position to assess whether the
verdict figure represented past infringement as well as
ongoing infringement. In the absence of an express
statement in the verdict, this court cannot determine
whether the jury compensated Telcordia for all of Cisco’s
infringing activities. The $6.5 million award is closer to
$5 million proposed by Cisco for past and ongoing in-
fringement than $75 million proposed by Telcordia for
past infringement only. However, neither party proposed
the exact $6.5 million figure. In any event, this court
holds that the district court’s finding that the jury’s
verdict compensates Telcordia only for past infringement
TELCORDIA TECH v. CISCO SYSTEMS 24

is not clearly erroneous. In the circumstances of this case,
this court finds that the district court did not abuse its
discretion in interpreting the verdict form.
C.
Title 35 provides for the calculation of damages “to-
gether with interest . . . as fixed by the court.” 35 U.S.C.
§ 284. In patent infringement cases, “prejudgment inter-
est should be awarded under § 284 absent some justifica-
tion for withholding such an award.” General Motors
Corp. v. Devex Corp., 461 U.S. 648, 657 (1983). Cisco
asserts that the jury’s damages award includes prejudg-
ment interest, thereby barring its award under sec-
tion 284. For the same reasons, the verdict form is
ambiguous as to whether the jury’s damages award
includes prejudgment interest. Because the district court
did not clearly err by concluding that the jury’s damages
award did not include prejudgment interest, the district
court’s award of interest under section 284 does not
constitute an impermissible double recovery.
D.
“Under some circumstances, awarding an ongoing
royalty for patent infringement in lieu of an injunction
may be appropriate.” Paice LLC v. Toyota Motor Corp.,
504 F.3d 1293, 1314 (Fed. Cir. 2007). If the district court
determines that a permanent injunction is not warranted,
the district court may, and is encouraged, to allow the
parties to negotiate a license. Id. at 1315. The district
court may step in to assess a reasonably royalty should
the parties fail to come to an agreement. Id.
In this case, after declining Telcordia’s motion for
permanent injunction, the district court directed the
parties to negotiate a reasonable royalty for ongoing
infringement. An award of an ongoing royalty is appro-
25 TELCORDIA TECH v. CISCO SYSTEMS

priate because the record supports the district court’s
finding that Telcordia has not been compensated for
Cisco’s continuing infringement. Therefore, the district
court did not abuse its discretion by directing the parties
to negotiate the terms of the appropriate royalty.
Accordingly, this court affirms the district court’s
grant of an accounting and prejudgment interest. As the
district court properly instructed the parties to negotiate
the royalty, this court remands to the district court so
that the parties can complete the royalty negotiation
process. If the parties cannot reach an agreement, the
district court should step in and assist or calculate on its
own the appropriate rate. Telcordia and Cisco will have
an opportunity to appeal the royalty set by the district
court.
VII.
Accordingly, this court vacates the district court’s de-
nial of Cisco’s JMOL motion on invalidity of the ’306
patent and remands for determination of the validity
issue. This court also remands to allow the parties to
negotiate the terms of the royalty. In all other respects,
this court affirms.
AFFIRMED-IN-PART, VACATED-IN-PART, and
REMANDED.
COSTS
No Costs.
 United States Court of Appeals
for the Federal Circuit
__________________________

TELCORDIA TECHNOLOGIES, INC.,
Plaintiff-Appellant,

v.
CISCO SYSTEMS, INC.,
Defendant-Cross Appellant.
__________________________

2009-1175, -1184
__________________________

Appeal from the United States District Court for the
District of Delaware in case no. 04-CV-876, Chief Judge
Gregory M. Sleet.
__________________________

PROST, Circuit Judge, dissenting-in-part.

I respectfully dissent on the narrow issue of indefi-
niteness discussed in Part V of the majority opinion in the
case. I do not agree that the patent disclosure here
clearly links the structure of the controller with the
claimed function of “evaluating the integrity of the multi-
plexed subrate communications on the first ring and the
second ring,” to the extent required by this court’s prece-
dent.

The patent specification describes the invention as
comprising nodes. Each node has a plurality of parts,
including a controller and a selector. The disclosure
TELCORDIA TECH v. CISCO SYSTEMS 2

states that “the node continuously monitors and evaluates
the integrity of the multiplexed subrate signals arriving
at the node.” U.S. Patent No. 4,835,763 (“’763 patent”)
col.3 ll.4-17. The disclosure only associates the monitor-
ing function with the node as a whole. At no point does
the specification reveal that the structure within the node
that performs the monitoring task is the circuitry of the
controller.

Furthermore, the specification dedicates ample text to
describing the function of the controller. The description
explains that the controller inserts error signals when the
node detects a fault in the ring. Id. Nowhere does the
specification mention that the controller is also the part of
the node that monitors and detects the faults when the
multiplexed subrate signals arrive. Indeed, by attributing
certain functions to the node as a whole and other func-
tions specifically to the controller, the disclosure implies
that the node structure associated with the monitoring
means is distinct from the controller structure associated
with the insertion of error signals.

The majority holds that one of skill in the art would
understand that the selector component is not capable of
performing the monitoring function, and by process of
elimination would deduce that the controller is the struc-
tural component of the node associated with the claimed
function. Majority Op. at 20-21. It is not enough, in my
view, that a skilled artisan can follow the clues in the
patent and solve the mystery of what structure must
perform the claimed function. See Tech. Licensing Corp.
v. Videotek, Inc., 545 F.3d 1316, 1338 (Fed. Cir. 2008).
Our precedent requires that the specification clearly link
a particular structure with a claimed function. See Bio-
medino, LLC v. Waters Techs. Corp., 490 F.3d 946, 950
(Fed. Cir. 2007); Tech. Licensing, 545 F.3d at 1338.
3 TELCORDIA TECH v. CISCO SYSTEMS

Accordingly, I would hold that the term “monitoring
means” is indefinite under 35 U.S.C. § 112 for failing to
disclose a structure associated with the claimed function,
and thus hold the asserted claim of the ’763 patent inva-
lid.